In a small glass jar or a medium mixing bowl, combine the extra virgin olive oil, apple cider vinegar, maple syrup, Dijon mustard, salt, and black pepper. Whisk the ingredients vigorously until they are emulsified and the dressing looks creamy and well combined.
If your walnuts are raw, place them in a small dry skillet over medium heat. Toast them for about 3 to 5 minutes, tossing frequently, until they become fragrant and slightly golden. Remove them from the heat immediately to prevent burning and let them cool for a few minutes before adding them to the greens.
Core the apples and slice them into thin wedges or matchsticks. If you are not serving the salad immediately, you can toss the apple slices in a tiny bit of lemon juice to prevent them from browning, though the acidity in the dressing will also help keep them looking fresh.
Place the baby arugula in a large salad bowl. Add the sliced apples and the cooled toasted walnuts. Drizzle about half of the prepared dressing over the top and toss gently with tongs or clean hands to coat the leaves without bruising them. Add more dressing as needed according to your preference.
Once the greens are lightly coated, sprinkle the crumbled goat cheese or feta over the top. Give it one very gentle final toss or simply leave the cheese on top for a beautiful presentation. Serve immediately while the greens are crisp and the apples are juicy.
